How to choose and care for cut flowers

Valentine’s Day is coming, and cut flowers make a great gift for your special person.

When buying cut flowers at any time of year, take a close look at the flowers to make sure they are fresh. Avoid buying bunches that have flowers with brown edges or petals that are starting to fall off.

To keep cut flowers fresh, place them in room-temperature water as soon as possible. Protect cut flowers from exposure to freezing temperatures outside. With a sharp knife or pruners, make an angled cut and remove at least 1 inch from each stem. Ideally, make this cut while the stem is under water. Cutting on an angle increases the surface area for water intake.

Add floral preservative to the vase water. Most preservatives contain an acid (to neutralize alkaline tap water) and an ingredient to discourage bacteria.

Remove all foliage below water level. Cut flowers prefer a cool, humid environment and should be kept out of bright light and away from heating vents. Do not place cut flowers near a bowl of fruit or vegetables, since the ethylene gas emitted by ripening fruit can damage flowers, as can cigarette smoke.

If healthy cut roses suddenly develop drooping heads, it may be due to air bubbles trapped in their stems. Float the entire stem in a sink full of warm water. Trim another inch from the stem, cutting on an angle below water level. Try to gently straighten the drooping flower head as the flower and stem continue to float and the cut end of the stem remains under water for at least a half hour. When the flower head hardens to a straightened position, place the roses back in the vase.

Recent snowstorms have put a nice covering of snow over gardens. This is generally good for your garden in providing some insulation when there are extremely cold temperatures. There is nothing special to do other than to monitor for rabbits that can now reach higher into plants to feed and deer whose tracks will be easy to see.

Try not to pile snow too deeply on deciduous and evergreen shrubs to avoid breaking branches. This is not always possible, and I have two evergreens at home that were flattened with heavy snow. They sprang up just fine once the snow melted. There’s no need to worry about piling snow on herbaceous plants and ground covers unless the snow is saturated with ice-melting salt that can damage plants.

• Tim Johnson is director of horticulture at Chicago Botanic Garden, chicagobotanic.org.